It is believed that contemporary fuel injectors can be designed to accommodate a particular engine in part to meet tailpipe emission standards. The ability to meet stringent tailpipe emission standards for mass-produced automotive vehicles is at least in part attributable to the ability to assure consistency in both shaping and aiming the injection spray or stream, e.g., toward intake valve(s) or into a combustion cylinder. Wall wetting should be avoided.
Because of the large number of different engine models that use multi-point fuel injectors, a large number of unique injectors are needed to provide the desired shaping and aiming of the injection spray or stream for each cylinder of an engine. To accommodate these demands, fuel injectors have heretofore been designed to produce straight streams, bent streams, split streams, and split bent streams. In fuel injectors utilizing thin disc orifice members, such injection patterns can be created solely by the specific design of the thin disc orifice member. This capability offers the opportunity for meaningful efficiency in manufacturing since other components of the fuel injector are not necessarily required to have a unique design for a particular application, i.e. many other components can be of a common design.
It is believed that known orifices can be formed in the following manner. A flat metering disc is formed with an orifice that extends generally perpendicular to the flat metering orifice disc, i.e., a “straight” orifice. In order to achieve a bending or split angle, i.e., an angle at which the orifice is oriented relative to a longitudinal axis of the fuel injector, the orifice can be formed by punching at an oblique angle relative to the longitudinal axis to provide an “angled orifice,” i.e., an orifice angled with respect to the planar surface of the metering disc or a longitudinal axis extending perpendicularly between the flat surfaces of the disc.
However, the punching of oblique or angled orifices in a metering disc has been observed to provide a less than desirable performance. In particular, the working end of the tool, which is oriented oblique to the workpiece, tends to break during the punching process. Even if the punch tool does not break during the angled orifice punching process, the punch tool may skip, slide, or deflect upon impact with the surface of the work piece and therefore could cause the work piece to be damaged and discarded. Further, the skipping sliding, or deflecting of the punch could cause the work piece to move around laterally or vertically. To avoid the movements of the work piece, a complex work piece retention arrangement is utilized to ensure that the work piece is stationary relative to a support surface.
Thus, it would be desirable to provide for a tool without the perceived disadvantages of the known punch tool.